Treadle mechanism



June 29, 1937. ELLIOTT 2,085,427

TREADLE MECHANI SM Original Filed May 20, 1955 VE/V 70%? M? 5% Patented June 29, 1937 UNITD STATES PATENT OFFICE TREADLE MECHANISM Original application May 20, 1935, Serial No.

22,302. Divided and her 6, 1935, Serial Britain July 13, 1934 6 Claims.

My invention relates to treadle mechanism of a character which may be employed advantageously in, for example, sole-rounding machines. Such a rounding apparatus is disclosed in Letters Patent of the United States No. 882,009, Mayo, March 17, 1908. The present case is a division of an application filed in the names of Joseph Gouldbourn and Harold E. Elliott in the United States Patent Office on May 20, 1935, for

10 improvements in Rounding machines, it bearing the Serial No. 22,302.

Machines of the class above mentioned usually have a treadle-operated mechanism, to be utilized for moving a clamping member into engagement with an article on a pattern, and in some machines it is necessary for the operator to hold the treadle depressed during the operation of the machine with a pressure sufiicient to resist movement of the article during rounding. The treadle mechanism has in some instances been so arranged that considerable movement of the treadle has been needed for the initial clamping. This has necessitated a corresponding raising and lowering of the operators foot, and the pressure 5 required on the treadle has called for undesirable exertion.

It is an object of the present invention to enable the operator to move a clamp or other member. to be actuated into engagement with the Work by a comparatively small movement of his foot on the treadle, and to eiiectively clamp the article on the pattern and hold it during the operation of the machine without undue effort. To this end, I associate with the member to be actuated, which may herein be considered as a rod or other element through which force is transmitted, a toggle and a treadle, together with connections by which the toggle may be moved from the treadle either bodily or may be straightened. In the first instance, the treadle movement produces rapid travel of the actuated element for a relatively small treadle-displacement. In the second, the leverage is increased to apply a comparatively heavy pressure while minimizing the efiort required on the part of the operator. During the latter effect, the treadle, which is preferably sectional, has a portion locked and its locking may be controlled by a section of the treadle itself, which also may be joined to the toggle to straighten it.

In the drawing,

Fig. 1 is a side elevation, partly in section, of one form of my improved treadle mechanism, and Fig. 2 is a sectional elevation on the line II-II 55 of Fig. 1.

this application Decem- No. 53,250. In Great I have shown herein, a two-part treadle-lever pivoted on a horizontal shaft I5I extending across a bracket I53 secured to the frame of the machine in which the mechanism is employed. The front section I55 of the lever is arranged to be depressed by the operator, and the rear section I51 is connected, through mechanism hereinafter described, to a rod I58 joined to the element of the apparatus to be controlled, as the work-clamp of a rounding machine. The sections of the treadle-lever have co-operating stop-faces IBI, normally held in contact by a spring I63 joining the treadle-sections but which may be separated by depression of the front section. The rear end of the section I51 has pivotally connected to it the lower extremity of a pair of upwardly extending toggle-links I55, I61. The upper end of the toggle-link I61 is joined to the central portion of a lever I69 fulcrumed at I1I on the bracket I53 and guided by a fork I93 rising from said bracket. To the free end of the lever the rod I58 is connected. The relation of the lever-arms is such that a comparatively small movement of the operators foot carries the element actuated by the rod I58 through its operating stroke. The rod I58 is formed in two parts, there being a spring I13 between them to provide a yielding link joining the toggle and the clamp. The center I19 of the toggle I55, I61 is connected by a forwardly extending link I15 to an arm I11 projecting upwardly from the inner extermity of the section I55 of the treadle-lever. When the front part I55 of the treadle-lever is raised, the toggle is broken rearwardly by the spring I63 acting through the link. The rear of the treadle-section I51 has pivoted on it a pair of depending pawls I8 I, I8 I arranged to engage the teeth of a ratchetblock I83 secured on the bracket I53. The pawls are of unequal length, so that when one of them is in engagement with a tooth of the block the other is engaging the block half Way between two adjacent teeth. The teeth of the ratchet-block are so disposed that, when one of the pawls is in engagement with them, the rear of the treadlelever is locked against downward movement. The pawls are moved by spring-plungers I85 into engagement with the ratchet-teeth, and have upwardly projecting arms I81 for engagement with an adjustable screw I89 projecting horizontally through a lug I9I on the under side of the link I15. When the treadle is raised and the toggle is broken, the pawls are held clear of the ratchetteeth by the screw.

When the treadle is depressed, its two sections move about their pivot I5I together, the spring I63 connecting them being sufiiciently strong to overcome the resistance initially encountered by the rod I58 in bringing the controlled clamp into contact with the work. At this time, the toggle is moved bodily, the angular relation between its links I65 and IE5! not being altered. Upon engagement with the work of the member actuated by the rod I58, upward movement of the rear end of the section I 5? of the treadle-lever is resisted, and further depression causes the section I55 to swing on its pivot Ital relatively to the rear part. During this movement, the link I75 is shifted forwardly, and the screw I89 in the link moves away from the arms I877 on the pawls and allows one of the pawls to engage the ratchet I83. Downward movement of the rear of section I57 is thus resisted during continued depression of the section I55. when this occurs, the link I15 straightens the toggle I65, I67 and work-clamping pressure is applied through the leverage thereof to the rod I58. The spring I13 between the two parts of the rod is compressed during the straightening of the toggle, and this spring exerts the clamping pressure. Therefore, this pressure is always substantially uniform for different work-thicknesses, since the combined movement of the two parts of the treadle-lever measures the thickness of the material, and the subsequent straightening of the toggle always compresses the spring M3 by about the same amount. The straightening of the toggle to apply the clamping pressure requires no undue exertion on the part of the operator, and the eiTort required by the operator to keep the toggle straightened during the operation of the machine is only that needed to overcome the tension of the spring I I53. When the operator releases the treadle, the spring 963 raises the section I55 of the treadle-lever and breaks the toggle, thereby relieving the pressure of the clamp on the workpiece operated upon. Toward the end of the upward movement of the lever-section I55, after the toggle has been broken, the pawls are withdrawn from the ratchet-block I83 by engagement of the screw I89, and the rod I58 is lowered by an unillustrated spring, lowering the rear end of the treadle, the sections of which now move together.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination with a work-clamping member to be actuated, of actuating connections therefor including a toggle which is normally broken, a treadle, connections between the treadle and toggle to move said toggle bodily and thereby produce contact of the member with the work, and other connections between the treadle and toggle to straighten said toggle to apply clamping pressure to the wor 2. The combination with a member to be actuated, of actuating connections therefor including a toggle which is normally broken, a treadle, connections between the treadle and toggle to move said toggle bodily, other connections between the treadle and toggle to straighten said toggle, and means for locking a portion of the treadle against movement in one direction during the straightening of the toggle.

3. The combination with a member to be actuated, of actuating connections therefor including a toggle which is normally broken, a treadle, connections between the treadle and. toggle to move said toggle bodily, other connections between the treadle'and toggle to straighten said toggle, and means for looking a portion of the treadle against movement in one direction during the straightening of the toggle and controlled by said treadle.

4. The combination with a connecting rod, of a treadle having two sections one of which is yieldable upon the other, a toggle joined at its extremities to said other section and to the connecting rod, a'link uniting the yieldable section of the treadle to the center of the toggle, and a spring connecting the treadle-sections to hold them in their normal relation and to permit their yield, said springmaintaining the toggle normally broken.

5. The combination with a connecting rod, of a treadle having two sections one of which is yieldable upon the other, a toggle joined at its extremities to said other section and to the connecting rod, a detent for locking said other section against movement, and a link uniting the yieldable section of the treadle to the center of the toggle and acting upon the detent to release the treadle-section.

6. The combination with a connecting rod, of a lever fulcrumed at a fixed point and pivoted at its opposite extremity to the connecting rod, a treadle having two sections one of which is yieldable upon the other, a toggle interposed between said other section and the lever, and a link uniting the yieldable section to the center of the toggle.

HAROLD ERNEST ELLIOTT. 

